Steps to reproduce
- Copy to new server (data & sql) -> old has PHP 7 and new PHP 7.1
- Try to login - I see Login form
- 500 Error - See error log
Expected behaviour
Normal Login 
Actual behaviour
500 Error
Server configuration
Operating system:
Debian 8
Web server:
Apache 2.4
Database:
SQL
PHP version:
PHP Version 7.1.13-1+0~20180105151310.14+jessie~1.gbp1086fa
ownCloud version: (see ownCloud admin page)
10.0.2.1
The content of config/config.php:
Logs
Web server error log
No error
ownCloud log (data/owncloud.log)
{"reqId":"I3mbXG0dfUY2m1qj7Zes","level":3,"time":"February 24, 2018 11:14:30","remoteAddr":"","user":"Admin","app":"PHP","method":"POST","url":"\/index.php\/login","message":"realpath(): open_basedir restriction in effect. File(\/var\/customers\/webs) is not within the allowed path(s): (\/var\/customers\/webs\/USER\/owncloud:\/var\/customers\/tmp\/USER:\/usr\/share\/php:\/usr\/share\/php5:\/tmp:\/dev\/urandom) at \/var\/customers\/webs\/USER\/owncloud\/lib\/private\/Files\/Storage\/Local.php#365"}